Calcium channel inhibitors (CCI's) and calcium channel activators (CCA's) are thought to affect calcium flux through membrane bound channels as their major site of action. The literature already contains reports of CCI's inhibiting PCP and amphetamine stimulation in animals. There are four major subclasses of CCI's, and each appears to have different biochemical and behavioral properties. Our animal studies have addressed the hetereogeneity of this class of drugs, and have been designed to test multiple CCI's in single animal behavior models. To date findings show that nifedipine-like CCI's block PCP stimulation, nifedipine or flunarizine blocks amphetamine-induced stimulation, co-administration of dilitazem or verapamil (but not nifedipine) with chronic haloperidol treatment inhibits the development of neuroleptic-induced apomorphine supersensitivity, but not amphetamine supersensitivity. Additional studies have suggested a complex interaction between dopamine receptor function and calcium channels.